Fluid motors



Feb. 22, 1966 w. c. Lovl-:LL ETAL.L

FLUID MOTORS 'l 4 Sheets-Sheet v 1 Filed March l5, 1962 Fell 22, 1966 w. c. L ovELL ETAL 3,236,157

FLUID MOTORS Filed March l5, 1962 4 Sheets-Sheet 2 XIII Feb. 22, 1956 w. c. LovELL ETAL 3,236,157

FLUID MOTORS 4 Sheets-Sheet 5 Filed March l5, 1962 y@ n.555 D m mf E 7.5. d, n wig. f MER.

Feb. 22, 1966 w. c. LovELL ETAL FLUID MOTORS 4 Sheets-Sheet 4 Filed March l5, 1962 INVENTOR. .ZZ/a//EPCL/Jvef/ faim/:md 5. e 7:51391* J 5u mmm-ys United States Patent O 3,236,157 FLUID MOTORS Walter C. Lovell, Hazardville, Conn., Edmund S. Lee III, Wilbraham, Mass., and Peter J. Gunas, Manchester, Conn., assgnors to The Gunver Manufacturing Company, Manchester, Coun., a corporation of Connecticut Filed Mar. 15, 1962, Ser. No. 179,880 12 Claims. (Cl. 91-224) The present invention relates to improvements in the construction of fluid motors.

The overall object of the invention is to provide an improved uid motor which has high size to power and weight to power ratios and which is economical to manufacture.

Another object lof the invention is to provide an irnproved fluid motor capable of being driven by either compressible or non-compressible fluids.

Another object of the invention is to provide an improved iiuid motor having a positionally driven rotary output.

A further object of the invention is to provide an improved fluid motor which is particularly adapted to be driven by waterpowcr as by being connected to the usual water supply found in most homes and businesses.

Ancillary to the last object, another object of the invention is to provide an improved portable liuid motor which may conveniently .be attached to a garden hose and employed to power various tools employed in yard work, as for example hedge trimmers, pruning saws, etc.

The basic motor of the present invention comprises a cylinder and a piston reciprocable therein, the piston having axial passageway means therethrough. A member also reciprocable in the cylinder is adapted tosealingly engage said passageway means. Means are provided for urging said piston towards one end of the cylinder and into sealing engagement with the sealing member. Means are then provided for introducing pressurized fluid into said one end ofthe cylinder to displace the piston and sealing member towards the other end of the cylinder. Means are further provided for limiting the movement of the sealing member so that it will be disengaged from the piston and then returning the sealing member towards said one end of the cylinder. Fluid is discharged from the other end of the cylinder as the piston is returned towards said one end and into engagement with said sealing member for a subsequent reciprocation.

Another aspect of the invention involves the provision of a fluid motor having a rotary output wherein the motor comprises a reciprocable piston positively driven in at least one direction by fluid pressure.

Another aspect of the invention comprises the basic motor above described wherein a second cylinder surrounds the first cylinder to provide an annular passageway through which the fluid, and particularly liquid, is discharged back towards the one end of the first cylinder. Where liquids are used as the power source this allows the liquid to be diverted from whatever tool is driven by the motor.

A further aspect of the invention comprises a water motor adapted to be connected to a garden hose or the like and lhaving, a power tool driven thereby. A hose is connected to the inlet of the motor and a second hose is connected to the discharge from the motor. The two hoses are coextensive in length for `a substantial distance from the motor where the discharge hose terminates at a point sufficiently remote that there is no danger of the operator getting wet. The first or inlet hose is accessible for connecting to the garden hose.

The above and other related objects and features of the invention will be app-arent from a reading of the following 3,236,157 Patented Feb. 22, 1966 ICC description of the disclosure found in the accompanying drawings and the novelty thereof pointed out in the appended claims.

In the drawings:

FIG. 1 is a longitudinal section of a fluid motor embodying the present invention;

FIG. 2 is a section taken on line II-II in FIG. 1;

FIG. 3 is a section taken on line III-III in FIG. 1;

FIG. 4 is a section taken on line IV-IV in FIG. 1;

FIG. 5 is a section taken on line V-V in FIG. 1;

FIGS. 6, 7 and 8 are schematic views illustrating the operation of the fluid motor of FIG. 1;

FIG. 9 shows a modified embodiment of the present invention;

FIG. 10 shows another modified embodiment of the present invention;

FIG. 11 shows a further modified embodiment of the present invention;

FIG. 12 is a section taken on line XII-XII in FIG. 11;

FIG. 13 is a section taken on line XIII-XIII in FIG. 11;

FIG. 14 shows a modified embodiment of the present invention particularly adapted to be driven by waterpower;

FIG. 15 is a sect-ion taken on line XV-XV in FIG. 14;

FIG. 16 is a section taken on line XVI-XVI in FIG. 14;

FIG. 17 is a section taken on line XVII*XVII in FIG. 14;

FIG. 18 is a section taken on line XVIII-XVIII in FIG. 14;

FIG. 19 is a drawing on a reduced scale illustrating the manner of using the fluid motor of FIG. 14;

FIG. 20 is a longitudinal section of a portion of a further modified embodiment of the invention;

FIG. 21 is a section taken on line XXI-XXI in FIG. 20;

FIG. 22 is a section taken on line XXII-XXII in FIG. 20; and

FIG. 23 is a fragmentary longitudinal section of yet a further modified embodiment of the invention.

The fluid motor seen in FIG. 1 comprises a cylinder 20 and a piston 22 :slidable therein and provided with an O-ring 24 to prevent leakage between the cylinder and the piston. As can be seen from FIGS. 1 and 3, the piston 22 is essentially cup-shaped wit-h a piston rod 26 secured to and projecting from its left-hand end. The rod 26 is slidably journaled in an end cap 28 which is threaded into the cylinder 20. Openings 30' communicate with the inte-rior of the cup-shaped piston 22 and provider an axial or longitudinal passageway therethrough.

A seat 32 is formed on the piston 22 at the right-hand end of the longitudinal passageway therethrough. A seal-` ing member 34 (FIGS. 1 and 4) is adapted to engage the seat 32 and seal olf this longitudinal passageway. The sealing member 34 is provided with vanes 36 which guide the sealing member for reciprocation within the cylinder.

20 so that the sealing member will accurately engage the seat 32 and seal off the longitudinal passageway when engaged with the piston 22.

The sealing member 34 is provided witha hub 38 at its opposite end. The hub 38 is grooved so that a tension spring 40 may be secured thereto by being threaded into said grooves. The opposite end `of the spring 40v is `similarly secured to a hub 42 on a retainer plate 44 which is mounted in the adjacent end of the cylinder 20.

Pressurized fluid is introduced into this end of the cylinder through a passageway 46 in a handle 48. The handle 48 is provided as a convenience in manipulating the cylinder 20 when a portable tool is attached to the fluid motor. A set screw `5t) is provided to retain the 'cylinder 201 'withinA a bore formed in the handle 48 with a fluid-tight connection being made between the cylinder and the handle. Means are provided for attaching a hose 52 to the lower end of the passageway 46. The hose 52 lis connected to a source of pressurized fluid and ow of luid to the cylinder 20 is controlled by a stem valve 56 secu-red to trigger 54. Normally the trigger 54 is urged outwardly by a spring 58 against a stop pin 60 so that the stem valve 56 seals off the passageway 48. Depression of the trigger 54 will bring opening 62 in the stem valve 56I into alignment with the passageway 48 to permit flow of fluid into the cylinder 20. It will be seen that holes 64 (FIGS. 1 and are provided in retaining plate 44 to permit the free flow of fluid into the cylinder 20.

FIGS. 1 and 6 illustrate the start or reset position of the fluid motor wherein the piston 22 is urged toward the right-hand end of the cylinder y by a compression spring 66. Spring 66 is centered by a hu'b 68 on the end cap 28 and a hub 70 on the piston rod 26. The passageway seat 32 is thus maintained in sealing engagement with the sealing member 34. Fluid pressure acting against the sealing member 34 and piston 22 forces these two members towards the lefthand or lower end of the cylinder 20. Fluid ow is indicated by the arrows in FIGS. 6-8. As this occurs the force exerted by tension spring 40 on the sealing member 34 progressively increases until the balance of fluid forces and spring forces on this sealing member causes it to disengage from the piston 22; this position just having been reached in FIG. 7. The relative spring forces are such that the sealing member 34 will be returned to its start position at the inlet end of the cylinder 20 as indicated in FIG. 8 and thereafter the piston 22 will be returned towards this same inlet end by the spring 66. The piston 22 will be forced against the sealing member -34 and that member will again seal the longitudinal passageway therethrough by engaging the seat and a subsequent reciprocation of ithe piston 22 will auto-matically result.

It will be evident from FIGS. 7 and 8 that when the sealing member 34 is separated from the piston 22, fluid will flow through the longitudinal passageway in the piston and then be discharged through openings 72 in the retainer 28 (FIGS. 1 and 2).

A chuck 74 is secured to the piston rod 26 to provide for the attachment of a tool as, for example, a le 76 which is partially illustrated. The rate of reciprocation of the piston 22 and the tool driven thereby may be controlled by the extent of depression of the trigger 54 as fluid is throttled going through the yopening 62 in the stem valve 56. The stroke of the piston 22 may be controlled by a stop screw 78 which is threaded through the retaining plate 44 and albuts the hub 38. The screw 78 has a smooth diameter 79 at, its outer end which projects through the end wall of the handle 48 so that it may be simply rotated by a screw driver using the slot provided in its outer end. An O-ring packing is provided to prevent leakage of iluid where the diameter 79 passes through the handle 48. Thus by threading the screw 78 into or out of retaining plate 44, the start or rest position of the sealing lmember 34 may be conveniently controlled and thereby the .start position of the piston 22 likewise controlled. The leftward travel of the piston 22 is substantially unaffected by this adjustment so that its end result is to cont-rol the stroke o-f the piston 22.

Referring now to FIG. 9, a modied embodiment of the invention illustrates a means for more accurately controlling the stroke of the reciprocating piston. In this embodiment a cylinder 80 is formed, as by swaging to provide a sliding journal for a piston rod 82 which is secured-to a piston 84 slidable with the cylinder 80. The piston 84 is also cup-shaped and has a longitudinal passageway therethrough formed in part by openings 86. The end of this passageway facing the uid inlet end of the cylinder is formed with a seat 88 lwhich is sealingly engaged by a sealing member 90. Vanes 92 guide the sealing member so that it will properly en-gage the seat 88. A retaining plate 94 is mounted at the fluid inlet end of the cylinder 80. The plate 94 is held in place against a snap ring 96 by a connector 98, which is threaded into the inlet end of the cylinder 80. A rod 100' passes through an axial bore in the retainer 94 and is threaded into the sealing member 90. A tension spring 102 is secured to hubs 104 and 106 on the sealing member 90 and retainer 94, respectively.

The basic principle of the operation of this motor is substantially the same as that for the motor previously described. Thus pressurized Huid is introduced through a hose 108 attached to connector 98, from an appropriate source, and passes through the openings 110 in plate 94 to displace the sealing member and cylinder towards the left or outer end of the cylinder 80. This movement continues until the head 112 of screw 100 bottoms against the retaining plate 94. A compression spring 114 may be provided to cushion any impact which would result from the head 112 engaging the retaining plate 94. In any event, these means positively limit the stroke of the sealing member 90 as it travels away from the inlet end of the cylinder 80 and insures a separation of the sealing member 90 and piston 86 after a predetermined length of travel. The sealing memberV 90 is then returned to its start position by the spring 102 and the piston 86 returned towards the inlet end of the cylinder 80 by a compression spring 116 as fluid is discharged through openings 118 surrounding the journal for piston rod 82. Because of the reduced cross section of the sealing member and also because of the fact that the spring 102 is not depended upon to separate the sealing member from the piston 22, the spring 102 is substantially lighter than the spring 40 previously described. This increases the force of the outward stroke of the piston 22 as the tension force thereon has been proportionately reduced.

The fluid motor of FIG. 10 is similar to the fluid motor of FIG. 9 and like reference characters are used to indicate corresponding parts. Tension spring 102 has been `eliminated and a compression spring 120 is interposed between the piston 84 and the sealing member 90. With this arrangement, the compression spring 116 is substantially stronger than the spring 120 and the piston 84 is forced by the spring 116 into sealing engagement with the member 90. As uid is introduced in the inlet end of the cylinder 80, the piston 84 and sealing member 90 are displaced to the outer end of the cylinder 80 until the head 112 of screw 100 engages the retaining plate 94 to separate the sealing member 90 from the piston 84. The sealing member 90 is maintained in spaced relation from the piston 84 by the spring 120 as both elements are returned toward the inlet end of the cylinder 80 by the spring 116. Since the spring 116 is stronger than the spring 120, the piston 84 will again seat on the sealing member 90 preparatory to a further reciprocation of the piston 84.

`In the embodiments of FIGS. 9 and 10 the length of stroke is controlled by threading the screw 100 into and out of the sealing member 90 to control the extent of its outward movement.

Referring now to FIGS. 11-13, the embodiment of the motor therein shown also comprises many components which are essentially the same as found in FIG. 9 and like reference characters are used to identify corresponding parts. A modified piston 122 is reciprocable within the cylinder 80 and has an axial passageway therethrough which is sealingly engaged by the sealing member 90. The sealing member is drawn towards the retaining plate 94 by a spring 102 having substantially the same characteristics as the spring 40 in FIG. 1. The spring 102 is secured at its opposite ends to hubs on the sealing member 90 and a retaining plate 94.

The piston 122 has an annular insert 124 press-fitted therein. The insert 124 has ratchet teeth 126 formed on its outwardly facing radial surface. A driving member 128 has teeth 130 disposed in opposed relation to the teeth 126. A retainer 132 is press-fitted into the outer end of the piston 122 to limit longitudinal movement of the driving member 128 toward and away from the insert 124. Instead of having a piston rod secured to the piston 122 there is a rotary drive shaft 134 which is journaled in the outer end of the cylinder 80, with collars 136 preventing axial movement relative to this journal. The inner end or shank 138 of shaft 134 has a square cross section and is twisted as is best seen in FIG. 11. The driving member 128 has a square opening 140, therein for receiving this twisted shank portion, see FIG. 13. It will be noted that tension spring 116, which urges the piston 122 towards the sealing member 90 has outwardly bent ends. One of these bent ends is received by one of the fluid discharge openings 118 and the other bent end is received by one of a series of holes 142 (FIG. 12) in the retainer 132. This effectively prevents rotation of the piston 122 relative to the cylinder 80.

The holes 142 (FIG. 12) in combination with openings 144 (FIG. 13) in the driving member 128 and the shell-like conliguration of insert 124 yand piston 122 provide a passageway through the piston 122 as in the other pistons previously described.

In operation when pressurized fluid is introduced through the hose S, the sealing member 90 and piston 122 are displaced towards the outer end of the cylinder 80. As this occurs, the teeth 130 of the driving member 128 will be forced into mesh with the teeth 126. The driving member 128 is thus held in fixed relation relative to the piston 122 and cylinder 80 and rotation is imparted to the shaft 130 by reason of the twisted square shank 136. When the sealing member is disengaged from the piston 122 by spring 102', the sealing member 90 returns towards the inlet end of the cylinder 80 as previously described. Likewise the piston 122 is also displaced towards this inlet end by the spring 116. During this return movement of the piston 122, the teeth are disengaged from the teeth 126 as the driving member is displaced from the insert 92. During the return movement of the piston, the drive member 128 may rotate freely relative to the piston 122 and there is no substantial torque applied to the rotary shaft 134. The shaft 134 is free to continue rotating in the direction that it was originally driven. If there is any flywheel affect on the shaft 134 it will continue rotation as if power were applied to it continuously instead of intermittently. In any event, the rate of reciprocation of the piston 122 is so rapid that the rotation of the member 102 is effectively constant.

The motors previously described have been capable of operating with either compressible or non-compressible uids. The same holds true for the motor seen in FIG. 14, however, this motor is particularly adapted to be driven by waterpower.

In FIG. 14 -a piston 150 is reciprocable within a cylinder 152. The piston is again cup-shaped and has openings 154 (FIGS. 14 and 16) which comprise part of a passageway extending through the piston and terminating in a seat 156. The seat 156 is sealingly engaged by a sealing member 158 (FIGS. 14 and 17) having vanes 160 insuring positive engagement with a seat 156. A retaining plate 162 is disposed within the cylinder 152 inwardly of'the inlet end thereof. The retaining plate 162 is formed at the end of the sleeve 164 which is telescoped Within the cylinder 152 and positioned therein by a shoulder 166. A rod 16S passes through .a sliding journal formed by hub of retaining plate 162. The rod 168 is threaded into the sealing member 158 and provided with an enlarged head 172. A compression spring 173 is coiled around the rod 168 and is positioned concentrically thereof by bosses on the hub 170 and rod 168. 'Ille spring 173 acting against the head 172 yieldingly displaces the sealing member 158 toward the inlet end of the cylinder 152. Holes 174 are provided in the plate 162 to provide for the flow of fluid therethrough.

A hub 175 is formed on the sealing member 158 to space the sealing member from the holes 174 so that they will not be sealed olf when the sealing member is in its illustrated rest position. It will also be noted that the journal for the rod 168 is relieved adjacent the sealing member 158 so that the rod may be threaded into or out of the sealing member 158 to provide for adjustment of the stroke of the piston 150, as will later be explained in greater detail.

A piston rod 176 is secured to the piston 150 and projects from the motor to power whatever tool is to be driven thereby. A compression spring 177 urges the piston 150 towards the inlet end of the cylinder 152 to bring the seat 156 into sealing engagement with the member 158. A flow reversing baille 179 is disposed at the outlet end of cylinder 152 and is spaced from the walls of said cylinder for the llow of water therepast.

A second cylinder 178 is disposed concentrically with the cylinder 152 and forms therewith an `annular passageway for the return of liquid discharged from the cylinder 152. The left-hand or outer end of the cylinder 176 is reduced to provide a sliding journal for the piston rod 176 and also to provide a seat for the spring 177. The reduced outer end of the cylinder 178 further provides a seat for the discharge end of the rst cylinder 152 which is convoluted at this point (FIGS. 14 and 15) to provide for the passage of uid from the interior of the cylinder 152 to the -annular passageway between the cylinders 152 and 17 8.

The cylinders 152 and 178 are maintained in assembled relation by la connecting unit comprising a connector 180 threaded onto the cylinder 178. The connector unit comprises an inner connector 182 spaced from the outer connector 180 by webs 184. The inner connector engages sleeve 164 and forces the shoulder 168 against cylinder 152 to thereby force the convoluted end of the cylinder 152 against the seat formed therefor at the end of the cylinder 178. The connector 182 has secured to its righthand end a hose 186 and the connector 180 has secured to its right-hand end a hose 188 which is concentric of and generally spaced from the hose 186. The hose 186 is advantageously provided at its outer end (FIG. 19) with a connector 190 which may be conveniently attached to a garden hose or some other -source of water power.

In operation pressurized water enters through the hose 186 and passes through the openings 174 and retaining plate 162 to displace the sealing member 158 and piston 150 towards the discharge end of the cylinder 152. This continues until the combined spring and water pressure forces on the sealing member 158 prevent its further displacement in the left-hand direction, thus causing it to separate from the piston 150. This principle of operation would be essentially the same las that described in connection with the motor of FIG. 1. However, the principle of operation illustrated by the motors of FIGS. 9 and 10 can also be employed by making the spring suiciently weak so that at the point of maximum movement of the sealing member 158 the force which the spring 173 exerts on the sealing member is not suicient to cause the sealing member to separate from the piston 158. Separation of the sealing member would then be obtained by the coils of the spring 173 abutting each other and forming means for limiting further movement of the sealing member 158 so that there is provided a positive stop which limits the movement of the sealing member and likewise controls movement of the piston 150. With this latter form of spring 173, the stroke of the sealing member 158 may be adjusted by threading the rod 168 into and out of the sealing member 158 and thus the stroke of the piston 150 can also be controlled.

In any event, when the piston 150 separates from the sealing member 158, water passes through the longitudinal passageway therein and is discharged from the left-hand end of the cylinder 152 as the member 158 is returned towards the inlet side of the cylinder by spring 173 and the piston is returned towards said inlet side by spring 177 until the piston 150 again engages the sealing member 158 to commence another cycle of operation. As water flows past the piston 150 it is directed into the bafiie 179 which tends to reverse the ow of the water and thereby creates a water pressure force on the piston 150 which increases the force of its return stroke. The water discharged from the cylinder 152 passes through the annular chamber between the cylinders 152 and 178 and then between the connectors 180 and 182 and finally between the hoses 186 and 188 to the end of the hose 188.

The motor yof FIG. 14 is intended to power garden tools and other tools where ywater power is readily available. Thus, la threaded portion 194 is formed on the outer end of the cylinder 178 and a groove 196 is formed with the outer end of the piston rod 176 so that a tool may be attached to the motor by means of the threads 194 and a mechanical connection made with the piston rod 176 by means of the groove 196. In FIG. 19 the motor is illustrated as driving fa hedge trimmer 198. It will be seen that the inlet and discharge hoses 186 and 188 are disposed coextensively for a substantial distance from the motor so that the operator is free to use the tool 198 without danger of getting wet as the hose 198 discharges rthe spent water yat a substantial distance from the motor.

The fluid motor shown in FIG. 20 is most advantageously, though not necessarily, used with pneumatic power. This motor comprises a cylinder 200 within which piston 202 and sealing member 204 reciprocate. As with the other pistons herein disclosed the piston 200 has a longitudinal passageway which terminates in a seat 206 facing and engageable by the sealing member 204. A stem or rod 208 projects from the sealing member 204 and is received by a journal in a Spider or retainer 210. The outer arms of the spider 210 `are captured between a shoulder on the cylinder 200 and an end cap 210 threaded therein. The end cap is provided with a fitting 214 for receiving a hose 216 which is connected to a source of pressurized air. A compression spring 218 is coiled around the stem 208 between the spider 210 and a head 220 formed on the stem 208.

It will be noted that the sealing member 204 is provided with a disc-like element 222 which is closely spaced from the interior wall of the cylinder 200. Thel element 222 which could also be separately formed is preferably circular in shape and spaced from the cylinder 200 a distance of approximately .010 inch with an internal cylinder diameter of 1.5 inches. The disc-like element provides an orifice means for controlling the flow of fiuid past the sealing member and preferably take the form of sharp edged orifice plate with the area of the orifice between 2.5% and 40% of the internal area of the cylinder.

The operation of .the present motor follows the same basic principles as have previously been described. That is, a spring, not shown, urges the piston 202 into sealing engagement with the sealing member 204. Air entering through the hose 216 displaces both the sealing member and the piston member away from the inlet end of the cylinder until the sealing member' reaches the outer extent of its stroke which may be controlled either by the force of the spring 218 or by the action of the coils of spring 218 abutting each other in the fashion previously described. In any event, when this separation occurs air is discharged through the passageway in the cylinder 202 and there is a flow of air past the sealing member 204. As the air flows past the sealing member it must pass through the annular orifice defined by the disc-like element 222. In passing through this orifice, there is a reduction pressure at the orifice itself and also a turbulence created on the discharge side of the sealing member. Further, there is a reduction in the rate of iiow of air through the passageway in the piston 202 and a consequent reduction in air consumption. The net result of providing this orifice effect is that the sealing member is able to return towards the inlet end of the cylinder more rapidly. The disc-like element thus assures full power from the motor which might otherwise be lost if an external force on the piston were to cause it to sealingly engage the sealing member before it had returned to its start position at the inlet endof the cylinder. If this latter event were to occur, the motor could stall with the piston displaced toward the outlet end of the cylinder. The described orifice means greatly increase the external force required to stall the motor. The smaller the orifice area, the greater this stalling force becomes and the more effective orice areas range between 2.5% and 10% of the internal cylinder diameter for obtaining maximum power on each stroke. On the other hand the preferred orifice area for maximum stroke power causes a slower operation of the motor so that operation within the broader limits of orifice area may be desirable for faster operation.

Another advantage which is derived from the provision of the disc-like element 222 in reduction of noise in the operation of the fluid motor where pneumatic power is used. When the sealing member is unseated from the piston 202 there is only a limited volume of air whichmay be explosively released at this point. Further gains in this respect are obtained by spacing the disc-like element closely adjacent the piston 202 to provide the utmost minimum of air which may be explosively released. In any event, the noise level is drastically reduced as compared to operation of the motor wherein release of the sealing member, in effect, places the supply line of pressurized air in direct communication with the discharge outlet for the motor.

FIG. 23 illustrates a motor which is essentially the same as that shown in FIG. 20 and like reference parts are employed to denote corresponding elements. The modified sealing member 204 is provided with streamlined surfaces on both sides of the disc-like element 222' so that return movement of the sealing member may be further facilitated.

All of the fiud motors above described may be powered by either non-compressible or compressible fluids, as previously mentioned, and are characterized in the fact that the piston is positively driven in one direction by fluid power and returned by yieldable means in lthe opposite direction. The described motors are capable of extremely i y high rates of reciprocation of the piston and are extremely efficient in that high power outputs may be obtained from relatively small motors and also in that the weight of these motors is quite small compared to the power which is obtained. Further, the rate of reciprocation of the piston and the length of its stroke may be selectively controlled, as desired, as has been illustrated in the various embodiments.

It is to be understood that the motors of the present invention have widespread utility and the uses herein described are for illustrative purposes. It will also be noted lthat the various features of the different embodiments of the invention may be combined in several different ways in order to obtain best results for a given application. In the same vein it will be understood that variations in the structural arrangement of these motors will occur to those skilled in the art within the scope of the inventive concepts which are to be measured by the appended claims.

Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is:

1. A fluid motor comprising a cylinder, a piston reciprocable therein, a sealing member reciprocable in said cylinder and engageable with one side of said piston, an inlet for introducing pressurized fiuid into the sealing member end of said cylinder to displace the sealing member and piston towards the piston end of the cylinder, discharge passageway means lfor exhausting fluid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, resilient means acting on said piston and opposing its movement toward the piston end of the cylinder, means disposed within the sealing member end of the cylinder for limiting movement of the sealing member towards the piston end of the cylinder to disengage the sealing member from the piston and returning the sealing member towards the sealing member end of the cylinder in spaced relationship from said piston, said resilient means providing the sole means for limiting movement of the piston after the sealing member is ldisengaged therefrom and returning the piston toward the sealing member end of the cylinder to reengage the sealing member lfor a subsequent cycle of operation.

2. A fluid motor comprising a cylinder, a piston reciprocable therein, said piston having a length approximating the inner diameter of said cylinder, a piston rod projecting from the piston beyond one end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized iluid into the sealing member end of said cylinder to displace the sealing member and piston towards the piston end of the cylinder, discharge passageway means for exhausting nid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, resilient means acting on said piston and opposing its movement toward the piston end of the cylinder, means disposed within the sealing member end of the cylinder for limiting movement of the sealing member toward the piston end of the cylinder to disengage the sealing member from the piston and returning the sealing member towards the sealing member end of the cylinder in spaced relationship from said piston, said resilient means providing the sole means for limiting movement of the piston after the sealing member is disengaged therefrom and returning the piston toward the sealing member end of the cylinder to engage the sealing member for a subsequent cycle of operation.

3. A fluid motor comprising a cylinder, a piston having a low mass reciprocable therein, a piston rod projecting from the piston beyond one end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized fluid into the sealing member end of said cylinder to displace the sealing member and piston towards the piston en-d of the cylinder, discharge passageway means for exhausting fluid from the sealing member end of the cylinder, said sealing member and said piston having formed thereon cooperative conical seat and plug portions disposed substantially on a 45 angle and providing the sole means for sealing the discharge passageway means, resilient means acting on said piston and opposing its movement toward the piston end of the cylinder, means disposed within the sealing member end of the cylinder for limiting movement of the sealing member toward the piston end of the cylinder to disengage the sealing member from the piston and returning the ram toward the sealing member end of the cylinder in spaced relationship from said piston, said resilient means providing the sole means for limiting movement of the piston after the sealing member is disengaged therefrom and returning the piston toward the sealing member end of the cylinder to engage the sealing member for a subsequent cycle of operation.

4. A fluid motor comprising a cylinder, a piston reciprocable therein, a piston rod projecting from the piston beyond one end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized uid into the sealing member end of said cylinder to displace the sealing member and piston towards the piston end of said cylinder, discharge passageway means including a passageway through said piston for exhausting Huid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, resilient means -acting on said piston and opposing its movement toward the piston end of the cylinder, means disposed within the sealing member end of the cylinder for limiting movement of the sealing member toward the piston end of the cylinder to disengage the sealing member from the piston and returning the sealing member toward the sealing member end of the cylinder in spaced relationship from said piston, said resilient means providing the sole means for limiting movement of the piston after the sealing member is disengaged therefrom and returning the piston toward the sealing member end of the cylinder to engage the sealing member for a subsequent cycle of operation.

5. A fluid motor comprising a cylinder, a piston reciprocable therein, a piston rod projecting from the piston beyond the end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized fluid into the sealing member end of said cylinder to displace the sealing member and piston toward the piston end of said cylinder, a discharge passageway means -for exhausting uid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, resilient means acting on said piston and opposing its movement toward the piston end of said cylinder, means for limiting movement of the sealing member toward the piston end of the cylinder to disengage the sealing member from the piston and returning the sealing member toward the ram end of the cylinder in spaced relationship from said piston, an abutment engaged by said sealing member as it is returned to the sealing member end of the cylinder, thus establishing an initial or start position for the sealing member, said abutment member being adjustable longitudinally of the cylinder to vary the initial position of the sealing member and thus to Vary the length of stroke of the piston, said resilient means limiting movement of the piston after the sealing member is disengaged therefrom and returning the piston toward the sealing member end of the cylinder to engage the sealing member for a subsequent cycle of operation.

6. A uid motor as in claim 5 wherein means are provided for adjusting the abutment means from the exterior of the uid motor.

7. A fluid motor comprising a cylinder, a piston reciprocable therein, a piston rod projecting from the piston beyond one end of said cylinder, a sealing member reciprocable in said cylinder and engage-able with said piston, an inlet for introducing pressurized fluid into the sealing member end of said cylinder to displace the sealing member and said piston toward the piston end of said cylinder, discharge passageway means for exhausting iuid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, resilient means acting on said piston and opposing its movement toward the piston end of said cylinder, means disposed within the sealing member end of the cylinder for limiting movement of the sealing member toward the piston end of the cylinder to disengage the sealing member from the piston and returning the sealing member toward the sealing member end of the cylinder in spaced relationship from said piston, said resilient means providing the sole means for limiting movement of the piston after the sealing member is disengaged therefrom and returning the piston toward the sealing member end of the cylinder to engage the sealing member for a subsequent cycle of operation, and means for controlling the rate of ow of pressurized Huid through the inlet into the sealing member end of said cylinder to thereby control the rate of reciprocation of the piston.

8. A fluid motor comprising a cylinder, a piston reciprocable therein, a piston rod projecting from the pis-ton beyond one end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized fluid into the sealing 'member end of said cylinder to displace the sealing member and piston towards the piston end of said cylinder, discharge passageway means for exhausting uid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, a compression spring acting against said piston and opposing its movement toward the piston end of said cylinder, a fixed mounting member spanning the cylinder at the sealing member end thereof, a tension spring connected at Ione end to said mounting member and atits opposite end yto said sealing member and urging the sealing member to a start position at the sealing member end of the cylinder, said piston engaging said sealing member in its start position, said ytension spring exerting a lesser force on said sealing member inV its start position than the opposing force of uid pressure therein, the force of said tension spring increasing with movement of the sealing member and piston to overcome the fluid pressure force and thus limit movement of the sealing member to disengage it from the piston and .return the sealing member to its start position in advance of the pistons being returned by the compression Vspring to engage the sealing member for a subsequent cycle of operation.

9. A uid motor comprising a cylinder, a piston reciprocable therein, a piston rod projecting from ythe piston beyond the end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized uid into the sealing member end of said cylinder to displace the sealing member and piston toward the piston end of said cylinder, discharge passageway means for exhausting uid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, a compression spring acting against said piston and opposing its movement toward the piston end of said cylinder, a xed mounting member spanning the cylinder at the sealing member end thereof, a tension spring connected at one end to said mounting member and at its opposite end to said sealing member and urging the sealing member to a start position at the sealing member end of the cylinder, a pin projecting from said sealing member through said mounting member and having a head engageable `therewith after the sealing member and piston have been displaced a predetermined distance toward the piston end of the cylinder to thus limit movement of the sealing member and disengage it from the piston whereupon the tension spring returns the sealing member Ito its start position in advance of the pistons return by the compression spring to engage the sealing member for a sub sequent cycle of operation.

10. A fluid motor as in claim 9 wherein the piston has a low mass, and further wherein the sealing member has fins engaging the cylinder and guiding the reciprocation of the sealing member therein, and the discharge passageway means include a passageway through the piston and sealing of the discharge passageway is provided by cooperative conical seat and plug portions on the sealing member and piston which are disposed substantially on a 45 angle and provide the sole means vfor sealing the discharge passageway means.

11. A fluid motor comprising a cylinder, a piston reciprocable therein, a piston rod projecting from the piston beyond the end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized fluid into the sealing member end of said cylinder to displace the sealing member and pis-ton toward the piston end of said cylinder, discharge passageway means for' exhausting 12 fluid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, a compression spring acting against said piston and opposing its movement toward the piston end of said cylinder, abutment means limiting movement of the sealing member towards the piston end of said cylinder to disengage the sealing member from the piston, a second compression spring disposed between the sealing member and piston and spacing the sealing member and the piston as the iirs't compression spring returns-the piston towards the sealing member end of the cylinder, stop means engaged by the sealing member when it is so returned and positioning thev sealing member in a start position Whereupon the first mentioned compression spring Will cause the second compression spring to be deflected as ythe piston again engages the sealing member for a subsequent cycle of operation.

12. A fluid motor comprising a cylinder, a piston reciprocable therein, a piston rod projecting from the piston beyond one end of said cylinder, a sealing member reciprocable in said cylinder and engageable with said piston, an inlet for introducing pressurized fluid into the sealing member end of said cylinder to displace the sealing member and piston toward the piston end of said cylinder, discharge passageway means for exhausting fluid from the sealing member end of the cylinder, said discharge passageway means being sealed by engagement of the sealing member and piston, a compression spring acting against said piston and opposing its movement toward the piston end of said cylinder, a fixed mounting member spanning the cylinder at the sealing member end thereof, a pin projecting from said sealing member through said mounting member and having a head on the free end thereof, a second compression spring coiled around said pin between the head and the mounting member, and providing the sole means for limiting movement of the sealing member toward the piston end of the cylinder and returning the sealing member to a start position at the sealing member end of the cylinder in advance of the pistons return toward the sealing member end of the cylinder under the influence of said first compression spring for engagement with the sealing member for a subsequent cycle of operation.

References Cited by the Examiner UNITED STATES PATENTS 165,027 6/1875 Riley 121-3 583,802 6/1897 Hartwig 74-127 807,452 12/ 1905 Franke: 121-3 890,065 6/ 1908 Kellow 92-110 1,072,701 9/1913 Collins 74-127 1,104,071 7/1914 Overly 121-34 1,132,063 3/1915 Bardeen 91-50 1,173,326 2/1916 Taylor 121-33 1,224,008 4/1917 Nelson 121-34 1,369,256 2,192.1 Mackle 121-33 1,861,042 5/1931 Zublin 91-49 1,910,644 5/1933 Smi-tlr' 91-50 2,620,162 12/ 1952 Pennington 121-18 2,873,093 2/1959 Hildebrandt et al. 91-50 2,758,817 8/'1956 Bassinger 121-18 '2,813,514 11/1957 Von Seggern 121-3 2,813,516` 11/1957 Dulaney 121-30 21,943,603 7/ 1960 B'assingeii 121-13 SAMUEL LEVINE, Primary Examiner.

KARL l. ALBRECHT, FRED E. ENGELTHALER, Examiners. 

1. A FLUID MOTOR COMPRISING A CYLINDER, A PISTON RECIPROCABLE THEREIN, A SEALING MEMBER RECIPROCBLE IN SAID CYLINDER AND ENGAGEABLE WITH ONE SIDE OF SAID PISTON, AN INLET FOR INTRODUCING PRESSURIZED FLUID INTO THE SEALING MEMBER END OF SAID CYLINDER TO DISPLACE THE SEALING MEMBER AND PISTON TOWARD THE PISTON END OF THE CYLINDER, DIS CHARGE PASSAGEWAY MEANS FOR EXHAUSTING FLUID FROM THE SEALING MEMBER END OF THE CYLINDER, SAID DISCHARGE PASSAGEWAY MEANS BEING SEALED BY ENGAGEMENT OF THE SEALING MEMBER AND PISTON, RESILIENT MEANS ACTING ON SAID PISTON AND OPPOSING ITS MOVEMENT TOWARD THE PISTON END OF THE CYLINDER, MEAND DISPOSED WITHIN THE SEALING MEMBER END OF THE CYLINDER FOR LIMITING MOVEMENT OF THE SEALING MEMBER TOWARDS THE PISTON END OF THE CYLINDER TO DISENGAGE THE SEALING MEMBER FROM THE PISTON AND RETURNING THE SEALING MEMBER TOWARDS THE SEALING MEMBER END OF THE CYLINDER IN SPACED RELATIONSHIP FROM SAID PISTON, SAID RESILIENT MEANS PROVIDING THE SOLE MEANS FOR LIMITING MOVEMENT OF THE PISTON AFTER THE SEALING MEMBER IS DISENGAGED AND RETURNING THE PISTON TOWARD THE SEALING MEMBER END OF THE CYLINDER TO REENGAGE THE SEALING MEMBER FOR A SUBSEQUENT CYCLE OF OPERATION. 